Tryptamine, serotonin and catecholamines: an immunocytochemical study in the central nervous system

Exploring the proteins and metabolites associated with male antennae responses to female exposure of Antheraea pernyi (Lepidoptera: Saturniidae) moths

Detection of sex pheromones of insects relies on the antennae. The female pheromone signal transmission in the male antennae ultimately initiates the courtship and mating behaviors of males. To investigate the proteins and metabolites involved in this neural transduction, integrative proteomics and metabolomics analysis including tandem mass tag (TMT) proteomic quantification and liquid chromatography tandem mass spectrometry (LC/MS)-based metabolomics was adopted for comparing proteomic and metabolic changes between the antennae of male moths following stimulation by females and the non-stimulated males of Antheraea pernyi (Guérin-Méneville, Lepidoptera: Saturniidae) in this study. A total of 92 differentially expressed proteins (DEPs) containing 52 upregulated and 40 downregulated proteins and 545 differentially expressed metabolites (DEMs) including 218 upregulated and 327 downregulated metabolites were identified from the antennae of female-stimulated male moths based on the proteome and metabolome data, respectively. Bioinformatics analysis was performed for the 45 DEPs and 160 DEMs, including Gene Ontology (GO), Clusters of Orthologous Groups (COG), and Kyoto Encylopaedia of Genes and Genomes (KEGG) enrichment analysis and Human Metabolome Database (HMDB) annotation. A number of DEPs and DEMs related to neural transmission of female pheromone signals in the male antennae of A. pernyi were screened, including tyrosine hydroxylase, cryptochrome-1, tachykinin, arylalkylamine N-acetyltransferase, cadherin-23, glutathione S-transferase delta 3, tyramine, tryptamine, n-oleoyl dopamine, n-stearoyl dopamine, and n-stearoyl tyrosine. The altered expression levels of those proteins or metabolites were speculated involved in regulating the neuron activity for enhanced transmission of neural impulses and continuous perception, reception, and transduction of female pheromone signals. Our findings yielded novel insights into the potential mechanisms in the antennae of male A. pernyi responding to female attraction.

Chaperon-like Activation of Serum-Inducible Tryptophanyl-tRNA Synthetase Phosphorylation through Refolding as a Tool for Analysis of Clinical Samples

Tryptophanyl-tRNA synthetase (TrpRS) expression alters in colorectal (CRC), pancreatic (PC), and cervical (CC) cancers. Here, phosphorylation of unfolded TrpRS and its fragments is stimulated by human cancer sera (CS; n = 13) and serum of rabbit tumor induced by Rous sarcoma virus, unaffected by donor sera (NS; 11/15) and abolished by alkaline phosphatase. At 20 years of follow-up, serum-inducible TrpRS phosphorylation found years before healthy donors (3/15) diagnosed with PC, CRC, or leukemia. I have examined a specificity of serum-inducible TrpRS phosphorylation and found, surprisingly, that serine phosphorylation of unfolded TrpRS is stimulated by anti-TrpRS rabbit antisera but is unaffected by rabbit nonimmune sera and antisera to other antigens. Anti-TrpRS immunoglobulin G (IgG) inhibits phosphorylation of full-length TrpRS and stimulates phosphorylation of its 20-kDa fragment. Phosphorylation of this fragment is stimulated also by CS but not NS. 2-Mercaptoethanol and cyclic AMP exerted synergistic inhibitory effect on TrpRS phosphorylation. Anti-TrpRS sera and casein act as chaperones increasing TrpRS phosphorylation through refolding. Histone-specific protein kinase activity in CS (n = 44) and anti-TrpRS sera was lower than that in NS (n = 11), rabbit nonimmune sera and antisera to other antigens. TrpRS inhibitors, tryptamine, and tryptophanol stimulate in vivo accumulation of enzymatically inactive, nonphosphorylated, aggregated and anti-TrpRS IgG refoldable TrpRS. Phosphorylation of postsurgical tissues (n = 18) reveals TrpRS in ovarian cancer (OVC) and CC but not in normal placenta and liver. In OVC, TrpRS phosphorylation increase correlates with elevated tryptophan-dependent ATP-inorganic pyrophosphate exchange. Although not inducing cancer, TrpRS triggers signaling concomitant with cancer.

Experimental evidence that the serotonin transporter mediates serotonin accumulation in LSO neurons of the postnatal mouse

During the same postnatal period of development when their terminal projection patterns in the midbrain are maturing, lateral superior olivary (LSO) neurons are immunoreactive for serotonin (5-HT). As there is no evidence that LSO neurons synthesize 5-HT, it is likely that they accumulate 5-HT via the 5-HT transporter. To determine if the 5-HT transporter is responsible for 5-HT inside postnatal mouse LSO neurons, pups (postnatal ages 5-6) were treated with fluoxetine and LSO neurons examined for 5-HT. We also evaluated whether LSO neurons containing 5-HT expressed the 5-HT transporter. To further rule out any potential synthesis of 5-HT, brainstem sections of mice at postnatal ages when 5-HT staining is the most robust were stained for the rate-limiting enzyme in the synthesis of 5-HT, tryptophan hydroxylase. Fluoxetine treatment reduced or in most cases, completely eliminated the number of neurons in the LSO stained for 5-HT. Postnatal LSO neurons containing 5-HT were immunoreactive for the 5-HT transporter; in older animals in which 5-HT was no longer observed in the LSO neurons, 5-HT transporter expression was similarly absent. Further, LSO neurons in mice at any age did not stain for tryptophan hydroxylase. These results indicate that LSO neurons express the functional 5-HT transporter to internalize 5-HT; this mechanism may serve to regulate extracellular 5-HT levels during maturation of their terminal endings in the inferior colliculus.

Synergic effects of tryptamine and octopamine on ophiuroid luminescence(Echinodermata)

In ophiuroids, bioluminescence is under nervous control. Previous studies have shown that acetylcholine is the main neurotransmitter triggering light emission in Amphipholis squamata and Amphiura filiformis. By contrast, none of the neurotransmitters tested so far induced luminescence in two other ophiuroid species, Ophiopsila aranea and Ophiopsila californica. The aim of this work was thus to investigate the putative involvement of two biogenic amines, tryptamine and octopamine, in light emission of three ophiuroid species. A. filiformis responds to both tryptamine and octopamine, mainly on its arm segments, while O. californica only responds to tryptamine stimulation. By contrast,tryptamine and octopamine do not seem to be involved in O. aranealuminescence control since none of these substances induced light emission in this species. The synergic effects of several other drugs with tryptamine and octopamine were also tested.

Immunolocalization of semicarbazide-sensitive amine oxidase in human dental pulp and its activity towards serotonin

The semicarbazide-sensitive amine oxidase (EC 1.4.3.6; SSAO) from crude homogenates of human dental pulp was shown to catalyse the oxidative deamination of 5-hydroxytryptamine (serotonin; 5-HT) with a K(m) of 318+/-52 microM. In this respect the human enzyme resembles that in pig dental pulp, but differs from SSAO in all other tissues studied, which are inactive towards 5-HT. A method is described for obtaining intact dental pulp in which the anatomical details are preserved. Extracted teeth are frozen in dry ice and later defrosted rapidly before being fractured in a mechanical vice, facilitating pulp removal. Immunohistochemistry showed SSAO in the odontoblast layer, nerve fibres and blood vessels. The presence of SSAO in nerves in dental pulp appears to be unique. Tryptophan hydroxylase, a key enzyme in 5-HT synthesis, was also demonstrated in nerves and the odontoblast layer of human dental pulp.